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1.13 - Testing injection quantity, leak-tightness and spray pattern of injectors
Test conditions
• Fuel pressure OK; testing => Page
.
- Remove intake hose between air mass meter and intake silencer.
- Unplug connectors from injectors.
- -> Unbolt fuel rail from intake manifold.
- Disconnect vacuum hose from fuel pressure regulator.
- Lift fuel rail off intake manifold together with injectors and support fuel rail.
- -> Place the injector which is to be tested into a measuring glass from injection quantity tester V.A.G 1602.
- Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine
control unit itself.
=>Page
- Bridge contacts 1 and 65 on the test box using test leads from adapter set V.A.G 1594. (This creates an
earth connection to one side of the fuel pump relay coil.)
Testing for leaks
- Switch ignition on.
Note:
Once the ignition has been switched on the fuel pump runs continuously, even if the engine is not running. This
is because when the ignition is switched on the fuel pump relay receives its positive voltage supply via the
central electrics. The negative voltage supply for the fuel pump relay comes via the cable bridge on the test
box.
- Check injectors for leaks (visual check). When the fuel pump is running, only 1 or 2 drops should escape
per minute from each injector.
Audi A8 1994 ➤
Motronic injection and ignition system (6-cylinder) - Edition 02.1999
40
24 - Mixture preparation, Injection
